For FX2LP, in the auto mode, whenever data comes from Host, it will be directly committed to peripheral domain. For inspecting the first byte, you can check it by reading EP2FIFOBUF[0]. (it can be done in both AUTO mode or Manual mode)

I am sorry, for OUT endpoints In AUTO mode, the packets will be committed to peripheral domain immediately. So CPU cannot take control over the packets after committing(CPU won't come in between). So it is not possible in AUTO OUT mode to access the packets.